Lightmap of mesh with artefacts

Development Asset Creation
1

Need solution for importing FBX-file from Blender to UE4. While building Lightmap in UE4 got artefacts.

  1. Imported OBJ-file to Blender.
  2. Grouped Ctrl-J objects.
  3. Normal textures in UVmap.
  4. Add UVmap001 and Smart UV Project.
  5. Result and export to FBX-file.
  6. In UE4 imported mesh has 3 UV channels.
  7. Change Lightmap coordinate index to 1.
  8. Lightmap builded with artefacts.

How export mesh from Blender to UE4 with non UV-islands overlap.

0_5
0_51207×572 24.4 KB

0_4
0_41258×1436 513 KB

0_3
0_31920×1040 312 KB

0_2
0_21920×2080 909 KB
0_1
0_11920×2080 465 KB

2

Hello there @KekC_CSM!

From what I can see from your screenshots, the artifacts could be caused by an overlap between your maps, most likely due Blender’s Smart UV Project.

For testing, I would suggest skipping the light map entirely from Blender, just import your texture UVs. Then, generate a lightmap UV from UE itself, by enabling “Generate Lightmap UVs” on import, or from the Static Mesh Editor.

You can find further details on how to work with UE lightmaps in the doc below: